Tyre mounting on aero rims

[Hanlon]

Encountered an absurd problem mounting a tyre on a 700c clincher "aero" rim and would be grateful for advice please. Bought a pair of budget "Madspeed 7" wheels on eBay just to hack around on - but I cannot get the tyre to seat evenly right round the rim on the rear wheel. One small section of the tyre seems to be riding high. The inner tube can't be pinched because I've ridden several miles on the wheel. I even tried fitting a different tyre - same problem. Really scratching my head on this one !

 

[DCLane]

It may be the wheel - are you sure it's an even rim?

 

[Cycleops]

Spin the wheel in the drops without the tyre and look for any irregularities in the rim.

 

[Hanlon]

Spin the wheel in the drops without the tyre and look for any irregularities in the rim.

Good idea - I only spun the wheel to gauge its "roundness" with the tyre mounted - out with the tyre levers again !

 

[Cycleops]

Not impossible of course for the tyre to be faulty.

 

[the snail]

Might just not have seated properly - try inflating to higher pressure, or letting some air out and bouncing the wheel on the ground, and see if it seats better.

 

[Ian H]

Is the bulge by the valve?

 

[Hanlon]

Update : I've realised the problem is a short section of the tyre is fitting too deep in the rim, rather than a section being raised up. I'd tried bouncing the wheel and was inflating tyres to 120 psi anyway.... I thought the very cheap poorly fitting rim tape provided with the wheels might have been to blame so replaced it with a Schwalbe high pressure tape. Same problem, in spite of removing and replacing the tyre another twice. I think there must be a design fault on these cheap wheels so I've requested to return them for a refund. It's eBay so fingers crossed ! I've always used Campag or Shimano/Mavic wheels - and you do tend to get what you pay for ! Thanks for all the advice chaps

 

[Racing roadkill]

Put the tyre up to a low pressure, and work the bead upwards around the circumference, with your thumbs, it will probably pop up into position. Another way to do it is to get the tyre roughly in position, then bang it up to pressure rapidly with a CO2 inflator.

 

[Hanlon]

I've now tried all the suggestions (except using a CO2 inflator) and also tried a THIRD different tyre - same result. I've been a cyclist for more than 40 years and changed hundreds of tyres of course - never encountered anything like it Now waiting to hear from the eBay business seller about returning the wheels. Thanks for all the help, chaps !

 

[Broadside]

I've now tried all the suggestions (except using a CO2 inflator) and also tried a THIRD different tyre - same result. I've been a cyclist for more than 40 years and changed hundreds of tyres of course - never encountered anything like it Now waiting to hear from the eBay business seller about returning the wheels. Thanks for all the help, chaps !

I’ve got some deep section rims on my main bike and the tyres are always difficult to mount fully, there is usually a flat spot - if mine were cheap wheels I might have blame that, but these are definitely not cheap wheels btw.

The CO2 method works if you inflate it fast in one hit, you can hear the bead finally snap in to the rim. Otherwise I inflate it to max pressure with a track pump and then after a few miles I will hear a snap as the bead finally seats. Once it snaps in to position the bead will stay there if you inflate and deflate so I then let some air out to run them at my usual operating pressure, it’s just getting the tyre on to the bead first time is very difficult.

 

[fossyant]

Talc or soapy water around the bead.

 

[Ian H]

You can take high-pressure tyres up to around 160psi for fitting purposes.

 

[Hanlon]

Thanks for all the helpful tips, chaps. But a very real issue here is what happens with a roadside puncture when you're 20 miles from home ?? Wouldnt want to be riding an egg shaped wheel all the way back, that's for sure ! As for budget versus quality aero rims - my "modern" De Rosa has Shimano Ultegra aero rims and I have NEVER had any problem whatever getting the tyres to mount properly